What does the new update has to offer? What are the changes? Should I do it? I have no time for factory reset after the update, is it going to be necessary?

Through it away and buy another brand phone.

The saddest thing of all is that there are OTA updates on an unofficial ROM and still no official updates.

It stays in place just by the silicon type glue it already has. You remove that and then you just pop it out and put the new one in its place and cover the small gaps with silicone. Here is the video I was talking about https://youtu.be/_gqXcHqiPQA?t=454 if you see it closely at 7:34 you will see a ...

I used an MS-polymer product.

I already done this three times if you talk about the main speaker. The best thing you can do is search for a Russian video in YouTube which shows how to change the charging board and follow from there until the speaker is visible. The admin has given the link in some different threads, maybe he can...

So, we are going back from battery drain to sudden reboots...

Which firmware do you have?

After 6 months of having the 20180124 because of the http://bbs.blackview.hk/viewtopic.php?f=191&t=369542 problem, today suddenly the cpu is working on full speed with no reason and battery started draining fast. I made it through the day 8 hour shift by having wifi, gps and Bluetooth turned off...

Maybe Android 8 will fix the issue.